The Fusaka Upgrade: An Overview And What It Means for Zircuit
Fusaka (Fulu-Osaka) went live on Ethereum mainnet on December 3, 2025. It’s a major upgrade designed to help Ethereum’s rollup ecosystem grow without becoming slower, more expensive, or harder to participate in. In this post, we’ll cover the most important changes Fusaka introduces, why they matter for Layer 2s, and what this upgrade means specifically for Zircuit.